Few things warm my heart faster than a financial trend that speaks to sanity, reason and foresight when it comes to retirement planning. And a new report released by Fidelity Investments says Americans are on the right 401(k) retirement track.

Fidelity says both employee and employer third-quarter 401(k) contributions in the 12 million accounts the firm administers increased, continuing a quarterly trend from 2009.

Indeed, an earlier Fidelity report from August said second-quarter average contributions from employees rose to $1,660 per quarter, up $150 from 2009. The average employer contribution rose to $950 for the quarter, up $90 from 2009.

Moreover, Fidelity says average annual savings by employees with Fidelity 401(k)s is now $5,900 compared to $5,500 in third-quarter 2007.

The net result of the increase in contributions and a run-up in the markets? The average Fidelity 401(k) account balance stood at $75,900 at the end of the third quarter, up 18% from the same time last year, a decent chunk of money to be sure.

Even more encouraging are some of other trends Fidelity uncovered in its August report, which included information from approximately 2.2 million 401(k) accounts held by Generation Y savers (italicized passages are mine):

Gen Y most properly allocated age cohort: Across all 401(k) participants, 45 percent are within +/- 10 percentage points of the Fidelity Freedom Fund equity rolldown schedule, a gauge the company uses to determine an age-based asset allocation that may be appropriate. But for Gen Y participants, that number jumps to 67 percent, illustrating how younger investors have embraced age-based asset allocation.

Roth 401(k) adoption rises, especially among youngest savers: The number of employers offering a Roth 401(k) savings option rose to 35 percent from only 10 percent five years ago. In plans that offer Roth 401(k), usage of the savings option is greatest among Gen Y participants with 8.8 percent contributing to them, versus 5.8 percent among all active participants.

As we’ve said on many occasions, retirement planning and savings aren’t just for middle-age or older folks. They’re for everyone starting at any age, and Fidelity’s news is welcome. And just in case you don’t know the rules for 401(k) contributions, a quick reminder: Contributions are limited to $17,000 for 2012, and $17,500 in 2013. Anyone over 50 can also set aside an additional $5,500 in each of those years.

Of course, another big question is how people want to invest for retirement, and indeed, whether they prefer 401(k) or similar retirement plans that force them to make their own investment decisions as opposed to traditional defined-benefit plans with their “guaranteed” pension payments, divorced from market ups and downs.

An excellent article by MarketWatch’s Andrea Coombes takes a look at this side of the issue and cites another study finding that workers are looking for help in managing their retirement nest eggs — and that many would trade paid time off and career advancement for guaranteed retirement benefits.

All of which makes for a mixed blessing: I’m pleased that more people, particularly younger people, are putting money away toward retirement. But I’m concerned that a large percentage are still concerned they won’t be able to manage that money.

No easy answers here, just a lot of food for thought, discussion and future columns, so stay posted.

Marc Bastow is an Assistant Editor at InvestorPlace.com. As of this writing he didn’t hold a position an any securities mentioned here, including Fidelity investment vehicles.